Disc shaped filter elements are known in the art. Disc shaped filter elements are for example used for the filtration of polymers for the production of polymer fibers, polymer films and polymer resin products. In polymer filtration filters need to capture impurities at the one hand and to shear the gels contained in the polymer at the other hand.
It is also known in the art to stack several disc shaped filter elements concentrically on a perforated tube. The particle loaded liquid is filtered through the disc shaped filter elements from the outside to the inside and the filtrate is discharged via the perforated tube.
Examples of disc-shaped filter elements are for example described in EP1862207 and EP284404.
EP1832207 describes disc shaped filter elements having a filter medium comprising metal fibers.
EP284404 describes disc shaped filter elements comprising a filter medium consisting of a porous sintered metal membrane and a porous sintered metal fiber membrane.
A problem associated with this type of disc shaped filter elements is that preferred paths are created during filtration. After a certain period of use, the shearing effect will end. The presence of preferred paths also means that there are “dead spots”. Dead spots are areas of stagnation, where liquid fluid such as the polymer melt stagnates.